Java使用icepdf将pdf文件按页转成图片

<dependency>
  <groupId>org.icepdf.os</groupId>
  <artifactId>icepdf-core</artifactId>
  <version>6.1.2</version> 
  <exclusions>
    <exclusion>
      <groupId>javax.media</groupId>
      <artifactId>jai-core</artifactId>
    </exclusion>
  </exclusions>
</dependency>

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriter;
import javax.imageio.stream.ImageOutputStream;

import org.apache.commons.logging.LogFactory;
import org.icepdf.core.exceptions.PDFException;
import org.icepdf.core.exceptions.PDFSecurityException;
import org.icepdf.core.p s.Document;
import org.icepdf.core.p s.Page;
import org.icepdf.core.util.GraphicsRenderingHints;


public class test20160929 {
  public static final String FILETYPE_JPG = \"jpg\";

  /**
   * 
   * 将指定的pdf文件转换为指定路径的图片
   * 
   * @param filepath 原文件路径，例如d:/test/test.pdf
   * 
   * @param imagepath 图片生成路径，例如 d:/test/
   * 
   * @param zoom 缩略图显示倍数，1表示不缩放，0.3则缩小到30%
   * 
   */
  public static void tranfer(String filepath, String imagepath, float zoom) throws PDFException, PDFSecurityException, IOException {
    Document document = null;
    float rotation = 0f;
    document = new Document();
    document.setFile(filepath);
    int maxPages = document.getPageTree().getNumberOfPages();

    for (int i = 0; i < maxPages; i++) {
      BufferedImage img = (BufferedImage) document.getPageImage(i, GraphicsRenderingHints.SCREEN, Page.BOUNDARY_CROPBOX, rotation, zoom);
      Iterator iter = ImageIO.getImageWritersBySuffix(FILETYPE_JPG);
      ImageWriter writer = (ImageWriter) iter.next();
      File outFile = new File(imagepath + new File(filepath).getName() + \"_\" + new DecimalFormat(\"000\").format(i) + \".\" + FILETYPE_JPG);
      FileOutputStream out = new FileOutputStream(outFile);
      ImageOutputStream outImage = ImageIO.createImageOutputStream(out);
      writer.setOutput(outImage);
      writer.write(new IIOImage(img, null, null));
    }
    System.out.println(\"转换完成\");
  }

  public static void main(String[] args) throws PDFException, PDFSecurityException, IOException {
    tranfer(\"d:/test/test.pdf\", \"d:/test/\", 1);
  }
}